This invention relates generally to a felling or harvesting head for harvesting trees, and, more particularly, to a harvesting head with opposing and spaced grapple arms, a dual post frame, a symmetrical accumulator pocket, and a tangent discharge chute.
A harvesting head is used in combination with a work machine, such as a harvester, to harvest or fell trees in the forestry industry. The harvesting head is generally mounted on a linkage attached to the work machine and placed near the tree being harvested. The harvesting head is then manipulated by the operator to engage and cut the tree. The operator may hold the cut tree on the harvesting head while cutting additional trees and then carry the accumulated cut trees to a central cut tree storage area, for greater efficiency. Generally, this is usually performed with smaller trees. Alternatively, however, the operator may cut a single large tree and carry it to the central cut tree storage area.
There are several difficulties associated with this harvesting operation. For example, due to the bulk and shape of the cut trees, it is often difficult to controllably carry them to the central cut tree storage area. The control of the holding action also becomes a problem when trees are being accumulated as they are cut. The configuration of the harvesting head may place a frame member in the operator""s line of sight and make it difficult for the operator to see the engaged tree. Also, the sawdust and debris from the cutting of the tree often clogs in the guard assembly of the harvesting head or, if there is no guard assembly, can uncontrollably exit the side of the harvesting head at a high rate of speed or can circulate in the base of the harvesting head and cause wear to the saw and other components. For better efficiency, it is important to have the capacity to carry the largest number of cut trees that the harvester can lift. Finally, it is desirable to hold the cut trees centrally in the harvesting head for better operator control and component life resulting from the decreased torque on the harvester linkage.
U.S. Pat. No. 5,004,026, issued Apr. 2, 1991 to MacLennan et al. (hereafter referenced as ""026) discloses a harvesting head of the type that accumulates trees and a method of operating same. ""026 is directed toward a harvesting head that minimizes splintering of the butt ends of trees while felling them, and that also minimizes losing them off the harvesting head after they are cut. The harvesting head of ""026 also has retaining means for loosely retaining the trees cut or being cut within tree receiving cradles provided on the harvesting head.
The harvesting head of ""026 has only one grapple arm, which may contribute to a loss of control of a cut tree by providing a pivot point about which the cut tree can rotate in a vertical plane, should the cut tree become unstable as it is carried. ""026 also does not appear to disclose several features claimed in the present invention, including a guard assembly for saw debris and a clear space between the posts of the saw for operator visibility.
Accordingly, the art has sought a method and apparatus of a tree harvesting head which: provides greater operator visibility; provides improved control of the cut trees; has more capacity for cut trees; can hold the cut trees centrally; provides a deflection and guard system for debris from the cutting device which is not easily clogged; may be used in a timely and efficient manner; and is more economical to manufacture and use.
The present invention is directed to overcoming one or more of the problems as set forth above.
In an embodiment of the present invention, a tree harvesting head is provided. The tree harvesting head includes an elongate frame, a first support device having a first grapple arm, a second grapple arm spaced from the first grapple arm, and a second support device having a collector mechanism and being located between the first support device and the second grapple arm. The elongate frame includes a central longitudinal axis, a first end portion, a second end portion, and a middle portion. The first support device and second support device each include a tree support member.
In an embodiment of the present invention, a tree harvesting head is provided. The tree harvesting head includes an elongate frame, a first support device, a second support device having a collector mechanism, a first grapple arm, a second grapple arm spaced from the first grapple arm, and a base portion. The elongate frame includes a central longitudinal axis, a first end portion, a second end portion, and a middle portion. The first support device and second support device each include a tree support member. The base portion includes a cutting device and a guard assembly. The guard assembly includes a deflector plate and a chute plate.
In an embodiment of the present invention, a method of harvesting trees with a harvesting head is provided. The method includes the steps of engaging a tree, cutting the tree, holding it with grapple arms while engaging it with a collector mechanism, and opening the grapple arms while holding the tree in an accumulator pocket with the collector mechanism.